Table 1.
Demographics of study population according to serum zinc level.
| Total | Serum Zinc Group | |||||
|---|---|---|---|---|---|---|
| Low, 0.0~79.9 |
Low–Normal, 80.0~100.0 | High–Normal, 100.1~120.0 | High 120.1~320.0 |
p-Value | ||
| N (%) | N (%) | N (%) | N (%) | N (%) | ||
| Total | 487 | 43 | 114 | 136 | 194 | |
| Serum zinc levels [mcg/dl], median (IQR) | 112.0 (95.0–142.0) |
69.4 (65.2–74.6) |
91.2 (86.3–96.1) |
109.2 (105.9–114.4) |
147.7 (134.6–175.2) |
|
| Age, year, median (IQR) | 67 (55–77) | 64 (51–77) | 71 (57–77) | 68 (58–78.5) | 64 (53–74) | 0.09 |
| Male sex | 334 (68.6) | 32 (74.4) | 79 (69.3) | 88 (64.7) | 135 (69.6) | 0.63 |
| Education, >12 years | 218 (44.8) | 19 (44.2) | 53 (46.5) | 53 (39.0) | 93 (47.9) | 0.43 |
| Pre-injury disability, GOS 1–4 | 9 (1.8) | – | 2 (1.8) | 4 (2.9) | 3 (1.5) | 0.75 |
| Comorbidities | ||||||
| Hypertension | 182 (37.4) | 14 (32.6) | 39 (34.2) | 54 (39.7) | 75 (38.7) | 0.71 |
| Diabetes mellitus | 122 (25.1) | 14 (32.6) | 28 (24.6) | 43 (31.6) | 37 (19.1) | 0.04 |
| Chronic liver disease | 22 (4.5) | 3 (7.0) | 4 (3.5) | 6 (4.4) | 9 (4.6) | 0.83 |
| Hemodialysis | 18 (3.7) | – | 7 (6.1) | 8 (5.9) | 3 (1.5) | 0.04 |
| Coagulopathy | 11 (2.3) | – | 7 (6.1) | 1 (0.7) | 3 (1.5) | 0.01 |
| Antiplatelet or anticoagulation | 61 (12.5) | 3 (7.0) | 17 (14.9) | 18 (13.2) | 23 (11.9) | 0.58 |
| Mechanism of injury | 0.02 | |||||
| Road traffic injury | 210 (43.1) | 18 (41.9) | 58 (50.9) | 49 (36.0) | 85 (43.8) | |
| Fall | 204 (41.9) | 12 (27.9) | 44 (38.6) | 66 (48.5) | 82 (42.3) | |
| Others | 73 (15.0) | 13 (30.2) | 12 (10.5) | 21 (15.4) | 27 (13.9) | |
| Prehospital alertness | 133 (27.3) | 6 (14.0) | 27 (23.7) | 34 (25.0) | 66 (34.0) | 0.02 |
| GCS in the ED, median (IQR) | 15 (9–15) | 12 (4–15) b,c | 15 (7–15) | 15 (11–15) | 15 (10–15) | 0.02 |
| Laboratory findings, median (IQR) | ||||||
| Hemoglobin [g/dL] | 12 (10–13) | 10 (8.8–11) a,b,c | 11 (10–13) b,c | 12 (11–13) | 13 (11–14) | <0.01 |
| Platelet [103/μL] | 194 (159–244) | 168 (144–228) | 200 (165–242) | 189 (152–245) | 198 (167–244) | 0.07 |
| PT INR | 1.0 (0.9–1.1) | 1.1 (1–1.2) a,b,c | 1.0 (0.9–1.1) | 1.0 (0.9–1.1) | 1.0 (0.9–1.0) | <0.01 |
| Types of intracranial injury | ||||||
| Diffuse axonal injury | 34 (7.0) | 4 (9.3) | 6 (5.3) | 7 (5.1) | 17 (8.8) | 0.47 |
| Subdural hemorrhage | 359 (73.7) | 30 (69.8) | 84 (73.7) | 99 (72.8) | 146 (75.3) | 0.89 |
| Epidural hemorrhage | 74 (15.2) | 8 (18.6) | 13 (11.4) | 28 (20.6) | 25 (12.9) | 0.14 |
| Subarachnoid hemorrhage | 200 (41.1) | 14 (32.6) | 51 (44.7) | 52 (38.2) | 83 (42.8) | 0.46 |
| Intracerebral hemorrhage | 115 (23.6) | 13 (30.2) | 33 (28.9) | 30 (22.1) | 39 (20.1) | 0.23 |
| Intraventricular hemorrhage | 41 (8.4) | 7 (16.3) | 7 (6.1) | 7 (5.1) | 20 (10.3) | 0.07 |
| AIS of head injury, 3–6 | 407 (83.6) | 38 (88.4) | 100 (87.7) | 110 (80.9) | 159 (82.0) | 0.36 |
| Injury severity score | 17 (10–25) | 22 (16–27) c | 19.5 (13–25) c | 16 (10–25) | 16 (9–22) | <0.01 |
| Transfusion in the ED | 127 (26.1) | 21 (48.8) b,c | 41 (36.0) b,c | 27 (19.9) | 38 (19.6) | <0.01 |
| Any operation | 138 (28.3) | 14 (32.6) | 30 (26.3) | 42 (30.9) | 52 (26.8) | 0.74 |
| Outcomes | ||||||
| ED mortality | 15 (3.1) | 1 (2.3) | 5 (4.4) | 3 (2.2) | 6 (3.1) | |
| 1-month GOS | 0.19 | |||||
| Death | 95 (19.5) | 15 (34.9) | 28 (24.6) | 24 (17.6) | 28 (14.4) | |
| Vegetative state | 6 (1.2) | – | 3 (2.6) | 1 (0.7) | 2 (1.0) | |
| Severe disability | 45 (9.2) | 3 (7.0) | 8 (7.0) | 14 (10.3) | 20 (10.3) | |
| Moderate disability | 38 (7.8) | 4 (9.3) | 8 (7.0) | 9 (6.6) | 17 (8.8) | |
| Good recovery | 303 (62.2) | 21 (48.8) | 67 (58.8) | 88 (64.7) | 127 (65.5) | |
| 6-month GOS | 0.35 | |||||
| Death | 103 (21.1) | 15 (34.9) | 29 (25.4) | 29 (21.3) | 30 (15.5) | |
| Vegetative state | 8 (1.6) | – | 2 (1.8) | 2 (1.5) | 4 (2.1) | |
| Severe disability | 33 (6.8) | 4 (9.3) | 6 (5.3) | 8 (5.9) | 15 (7.7) | |
| Moderate disability | 35 (7.2) | 4 (9.3) | 8 (7.0) | 8 (5.9) | 15 (7.7) | |
| Good recovery | 308 (63.2) | 20 (46.5) | 69 (60.5) | 89 (65.4) | 130 (67.0) | |
Abbreviations: IQR—interquartile range; GOS—Glasgow outcome scale; GCS—Glasgow coma scale; ED—emergency department; PT INR—prothrombin time international normalized ratio; AIS—abbreviated injury scale; a Bonferroni-adjusted p-value < 0.05 compared with the low–normal group; b Bonferroni-adjusted p-value < 0.05 compared with the high–normal group; c Bonferroni-adjusted p-value < 0.05 compared with the high group.